Tuesday, mankind visits its first unexplored world since 1989 – and its last for a long time, if not ever.

The NASA spacecraft was scheduled to be 7,750 miles from the dwarf planet’s surface at precisely 7:49:59 a.m., the pinnacle of a 9 1/2-year, 3 billion-mile journey for the spacecraft designed, built and managed by scientists at the Johns Hopkins Applied Physics Laboratory in Laurel.